<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .demo{
            width: 100px;
            height: 100px;
            position: relative;
            background-color: #ff5628;
        }
    </style>
</head>
<body>
<input type="button" value="开始">
<div class="demo"></div>
<script src="../jquery-1.12.4.js"></script>
<script>
    $(function () {
       $("input:eq(0)").click(function () {
           $(".demo").animate({left:400},2000,"linear",function () {
               console.log("233")
           })
       });
    });
</script>
</body>
</html>